Stay-in-place concrete form

ABSTRACT

A stay-in-place concrete form includes masonry shells layered with rigid insulation tied with plastic cross tie assemblies. The masonry shells can be connected with plastic dovetail connectors that compensate for the variation in height of the shells. This allows for the shells, together with the connectors, to be a consistent height and allows for dry stacking. The masonry shells can be bonded together with a layer of lightweight concrete poured in a cavity behind the masonry shells and/or bonded together by mortar joints. This dry stacking method can result in labor time and training savings over conventional masonry mortar construction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of U.S. provisional application No. 61/625,447, filed Apr. 17, 2012, the contents of which are herein incorporated by reference and U.S. Non-provisional application number 13/590,118, filed Aug. 20, 2012.

FIELD OF THE INVENTION

The present invention relates to concrete forms and, more particularly, to a stay-in-place concrete form including masonry shells layered with rigid insulation tied with plastic connectors.

BACKGROUND OF THE INVENTION

Concrete Masonry Units (CMU) are used in the construction of walls in buildings but have disadvantages that are costly to overcome. Block construction involves stacking CMU blocks in a grid pattern (typically 16″×8″ grid) to form a wall. CMU is manufactured in a molding process that results in blocks that can vary in size plus or minus ⅛″ within the height of the block. One end of the block can be ⅛″ lower than the other end of the block. The interior face can be a different height than the exterior face and the interior face can be different heights along its length.

Dry-stacking blocks with these inconsistencies in height would result in a wall that is out of plumb and out of level. The masonry industry has solved this problem by manufacturing CMU blocks to a size (typically 15⅝″×7⅝″) slightly smaller than the grid size. These masonry blocks are then stacked with a bed of mortar (typically ⅜″), to compensate for the smaller size, keeping the wall construction in line with the grid pattern established. A skilled mason lays mortar on the previous course of CMU blocks thicker than required, stacks the next course of block on top of the mortar and taps on the top of the block until he compresses the mortar down and out so that the combination of the block and the mortar lines up with the grid pattern.

This process results in mortar thickness that varies to compensate for the inconsistent heights of plus or minus ⅛″ in CMU masonry units and allows for the construction of plumb and level masonry walls.

This is a labor and skill intensive process that results in increased cost of construction versus other forms of construction.

Cement and aggregate also have high thermal conductivity. Energy required to heat or cool a house can more easily bridge through concrete masonry blocks. Even when insulation is inserted in the cores of block construction the energy still bridges through the concrete webs of the blocks.

Most home construction consist of walls constructed from 2×6 wood framing. 2×6 wood walls can be assembled in panels on the ground and tilted into place. The wall studs often come cut to length from the lumber yard and the skill to nail the panels together are minimal such that special training is not required.

While the cost of lumber is increasing and can be around the same or more that the cost of materials for a CMU block wall, the cost of labor to construct a block wall results in an overall cost that is much greater than 2×6 wall construction.

2×6 walls can also be insulated more easily than CMU block walls. Wood has a lower rate of thermal conductivity. Insulation can easily be installed between 2×6 studs and many products are available for this purpose. Energy bridging occurs at a much slower rate through 2×6 studs then it does through the concrete webs of CMU blocks.

The disadvantage of 2×6 wood wall construction is that the nailed connections are more easily torn apart in wind events or other natural disasters. Wood construction is also susceptible to fire damage.

Concrete walls are strong and can resist the forces from wind and other natural disasters. Concrete walls are also non-flammable. The labor to form up a concrete wall and then tear down the forms after the concrete has cured is expensive. Additional steps are required to insulate concrete walls. Concrete walls have an unpleasant appearance and steps must be taken to provide a finish. These factors make formed in place concrete wall unsuitable for house wall construction.

Insulated Concrete Forms (I.C.F.) construction has solved most of the problems of formed in place concrete by providing a rigid insulation form that does not have to be taken back down as the form stays in place after the concrete has cured. The form that stays in place also provides insulation for the concrete wall and covers up the unsightly concrete. Most systems also provide easy attachment points for exterior and interior finishes.

Insulated Concrete forms are made of rigid insulation blocks that are formed or cut with interlocking geometric shapes of precise dimensions. These interlocking insulation boards are expensive to manufacture and there are no set dimensions from manufacturer to manufacturer. The contractor is locked into a proprietary system and the systems are not interchangeable. The design is limited to the configurations offered by a particular manufacturer.

The lack of industry standards in grid layout and interchangeable parts has held back the I.C.F. Industry. The high cost of manufacturing the rigid insulating blocks is another factor that has limited the market share of this new technology. I.C.F. Blocks are also susceptible to insect infestation as the relatively soft insulation is exposed to the exterior soil line providing a path for insect tunnels to wood portions of the construction.

I.C.F. Blocks need extensive bracing to hold the forms plumb until the concrete core cures. The rigid insulation shells have a low modulus of elasticity and minor horizontal loadings can displace the forms out of plumb.

The present invention solves many of the problems associated with insulating concrete forms.

The present invention is an improvement on the concept of I.C.F blocks, a stay in place concrete form system consisting of modular units with shells that snap together and are connected together by plastic cross ties to resist the hydraulic pressure of poured in place concrete. The shells remain in place to provide insulation on both sides of the concrete wall. This also saves the labor involved in removing the form work.

The present invention improves on the I.C.F. Concept by making the snap together shells a shell of concrete masonry units and rigid insulation board combined together instead of just rigid insulation acting by it self.

The following benefits are achieved by this combination. The CMU provides a barrier between the soil and the rigid insulation to impede insect infestation. The CMU and rigid insulation together form a shell that is much more rigid reducing the need to brace the forms until the concrete core is poured. The CMU shell and rigid insulation can be positioned with a gap between them to accept mortar from behind the CMU. This adds even more to the stiffness of the shells and reduces the need for bracing even further. When perlite insulating mortar is used the moisture, sound, insulation, vapor barrier properties of the whole assembly is improved. The rigid insulation twists and stacks behind the CMU blocks. This eliminates the need for expensive procedures and molds required to form the rigid insulation segments normally used to achieve shapes that snap together. Under the present invention the rigid insulation is simple squares with clipped corners that are confined by plastic web members. The cost of the rigid insulation is greatly reduced. The rigid insulation in I.C.F. Forms are restricted to predetermined thicknesses. Under the present invention the rigid insulation can be stacked to provide as little or as much insulation as required by the designer. The total width of the concrete core plus the rigid insulation can be increased by changing the length of the plastic cross tie. The parts come separately to the field such that custom configurations can be arranged on site. The masonry shell can act as an exterior finish while I.C.F. Blocks require a finish layer to be added. The masonry shell are a better surface than the I.C.F. Blocks to accept finishes if an alternate finish is desired. The masonry shell protects the rigid insulation from wind borne damage.

A stay in place form using masonry shells would not normally be economically competitive with 2×6 stud wall construction due to the high labor and skill requirements involved with stacking mortared shells. The present invention solves this problem by providing plastic connectors that properly space the shells apart while allowing them to be snapped together. The mortar can then be patched or pointed in later. This procedure greatly reduces the skill required and the amount of labor required allowing the assembly to by more competitively priced with 2×6 wood stud wall construction while providing greater resistance to external forces such as wind and also meeting the insulation values required by current standards. The present invention also provides superior resistance to the effects of fire.

The twist and stack rigid insulation configuration also facilitates alternate mortaring methods.

Mortar is normally applied between blocks. The rigid insulation can be slid out to come in contact with the back of the concrete masonry unit shells on both the exterior side of the form and the interior side of the stay in place form. Alternately the rigid insulation segments can be slid in to allow the concrete masonry units to be mortared together behind the units in the cavity created in front of the rigid insulation segments.

Mortaring the concrete masonry units from behind allows the gap between the units to be reduced to ⅛″ from the traditional ⅜″ gap as the units are bonded together by an alternate method. This method would also allow other shell materials to be substituted for the concrete masonry units that normally would be too thin to mortar between the units. One example would be thin cement blocks produced to compatible dimensions to block coursing.

Formed concrete walls do not have a desirable appearance and require additional steps to insulate and finish when used as a structural wall in buildings. Blocks mortared in place require skilled laborers with extensive training. Mortared blocks must come assembled and therefore must be lifted over reinforcement or other vertical obstacles that are required to be embedded in concrete wall construction.

Conventional stay-in-place masonry forms come in the form of blocks that needed to be mortared into place, the same as normal masonry construction.

As can be seen, there is a need for an improved stay-in-place concrete form that can be assembled around obstacles, can be dry stacked

SUMMARY OF THE INVENTION

In one aspect of the present invention, a method of connecting concrete masonry shells together with plastic connectors that adjusts the height and width of the shells to a consistent height and width for use in a stay in place concrete form.

The plastic connectors are configured to fit tightly in a channel formed in the masonry shell. The friction from the tight fit of the assembly with the channel formed in the masonry unit and/or between the plastic connectors allows for the height of the shell unit and the plastic assembly combined to match a predetermined block coursing. Force is applied to the assembly (such as tapping with a rubber mallet) reducing the height of the assembly by sliding a tongue in the assembly into a receiver in the assembly. The force is discontinued when the assembly meets the height requirements. The friction resistance between the tongue and the receiver must be great enough to hold up the weight of the block above but small enough to allow movement when the external force (tapping rubber mallet) is applied.

The plastic assembly would also have a tab or connector formed as part of the assembly to accept a geometric plastic tie of uniform shape. The plastic ties would connect an interior and exterior shell assembly together the combination of which will act as a stay in place concrete form.

In one embodiment, the plastic ties consist of ½″ diameter pvc plastic pipe. The plastic ties are of uniform geometric shape. The plastic ties can be cut to any length. The thickness of the concrete wall formed inside of this cavity is determined by changing the length of the plastic ties to match the desired concrete wall thickness plus the desired insulation thickness. The plastic ties fit over a connector formed in the plastic assembly that is part of the shell assembly of consistent height on both the exterior and the interior. The plastic tie is either glued or screwed to the tab on the plastic assembly.

Rigid insulation segment are configured to fit tightly between the grid of plastic ties that tie the interior and exterior form walls. The rigid insulation segments are placed between the ties by inserting the segments between the ties from above at an angle. Twisting the rigid insulation segments parallel to the exterior and interior shells traps the insulation segments between the plastic ties. The insulation inserts can then be slid along the plastic ties into position next to the interior or exterior shell. This step is repeated until the desired insulation value is achieved on both the interior and exterior sides of the concrete form. Multiple layers of insulation can be positioned on both sides as more insulation value is required.

The gaps formed by suspending the masonry units apart through use of the plastic connectors described above are pointed or patched one course at a time. The process listed above is repeated course by course until the stay in place concrete form reaches the desired height.

When the shells on the interior and the exterior and the rigid insulation segments and the plastic ties are assembled to the desired height, course by course, then concrete is poured between the shells and the insulation to complete the stay in place assembly.

In another aspect of the present invention, the rigid insulation segments are positioned with a gap between the insulation and and the shell units. Mortar can then be filled between the blocks and/or behind the block. The mortar behind the block would overlap the units from behind to bond the blocks together from behind as well as between the blocks.

Providing additional bonding behind the blocks has the advantage of providing greater stiffness to the assembly one course at a time reducing the need for wall bracing until the center concrete core is poured as is generally required for most ICF systems.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an exploded plan view of a concrete form according to an exemplary embodiment of the present invention;

FIG. 1B is a side sectional view of the concrete form of FIG. 1A;

FIG. 2A is a plan view of the concrete form of FIG. 1A with the parts shown attached together;

FIG. 2B is a isometric sectional view showing a step-wise dry-stack construction of the concrete form of the present invention;

FIG. 3 is a isometric sectional view showing the plastic connector assembly being disposed on the masonry shells of the concrete form of the present invention;

FIG. 4 is a sectional view showing assembly of the components of the concrete form of the present invention;

FIG. 5A is a plan view showing installation of the rigid insulation form liner of the concrete form of the present invention;

FIG. 5B side view of a rigid insulation form liner used in the concrete form of the present invention;

FIG. 6A is a plan view showing the step-wise construction of the concrete form of the present invention as the lightweight concrete insulation is added; and

FIG. 6B is a section view showing the step-wise construction of the concrete form of the present invention as the lightweight concrete insulation is added as each row is added.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Broadly, an embodiment of the present invention provides a stay-in-place concrete form including masonry shells layered with rigid insulation tied with plastic cross ties. The masonry shells can be adjusted with plastic connectors that compensate for the variation in height of the shells. This allows for the shells, together with the connectors, to be a consistent height and allows for dry stacking. The masonry shells are bonded together with mortared joints after the shells are placed or with a layer of lightweight concrete poured in a cavity behind the masonry shells. This dry stacking method can result in labor time and training savings over conventional masonry mortar construction.

Rigid insulation segments are inserted from above and twisted and slid between the masonry shells and position behind either the exterior or the interior shell. This twist and stack method allows the laborer to add multiple layers of rigid insulation to each core as directed by the designer. Unlimited configurations of insulation are possible with this method of construction.

Rigid insulation segments can also be positioned with a gap between the shell and the rigid insulation. This configuration creates a cavity behind the shells. This cavity can be used to mortar the shells together from behind along with or instead of the standard method of mortar between the shells.

Conventional formed concrete walls do not have a desirable appearance and require additional steps to insulate and finish when used as a structural wall in buildings. The present invention solves this problem.

Stay-in-place forms eliminate the need to strip off temporary forms for concrete wall construction. Adding insulation to the concrete wall in a later step is not required as insulation is integrated into the stay-in-place form of the present invention. The stay-in-place form can act as an exterior and/or interior wall finish that is desirable to the end user.

Prior to the present invention, stay-in-place block forms came in the form of blocks that needed to be mortared into place, the same as normal masonry construction. The present invention simplifies the installation of mortar joints, allows for two layers of lightweight concrete adding to the insulation value of the assembly while also improving fire resistance, moisture resistance, and sound deadening characteristics. The present invention can be assembled in the field which allows for this assembly to be constructed around construction obstacles such as vertical rebar reinforcement in concrete and/or embedded utility piping.

With the concrete forms present invention, the masonry shells can be installed with plastic telescoping connectors that compensate for the variation in height of the shells. This allows for the shells with the connectors together to be a consistent height and allows for dry stacking. The masonry shells are bonded together with a layer of lightweight concrete poured in a cavity behind the masonry shells and/or masonry shells are bonded together by mortar joints. This dry stacking design of the present invention can result in labor time and training savings over conventional block mortar construction.

Concrete wall forms consist of two vertical surfaces connected by ties spaced at close intervals so that when concrete is poured between the two surfaces they are held in place by equal and opposite forces induced by the wet concrete.

Referring now to the Figures, a form cross tie 10, typically made from ½″ diameter plastic pipe, combined with connectors 12, typically made of plastic such as polypropylene, can act as a tie to prevent the vertical surfaces of the concrete form of the present invention from separating under the pressure of wet concrete. The form cross tie 10 also can act as a guide to retain and position the rigid insulation 50 into one stay-in-place concrete form unit. The form tie connectors 12 can be positioned in the top of a channel 22 formed in the exterior and interior shells 20, typically made of concrete masonry units, to position the shells to the required width. A second receiver connector 40 can be positioned in the bottom of a channel 22 formed in the exterior and interior shells 20 to act as a receiver to a tongue 14 formed as part of the form tie connector 12. The next course of of concrete form shells 20 can be attached to same item from the previous course by inserting the receiver channel 44 formed in the receiver connector 40 onto the tongue 14 formed in form tie connector 12. The connection of two levels of shells 20 with form tie connectors 12 at the top of the previous shell 20 and receiver connector 40 at the bottom of the next shell 20 can result in a height that matches a set standardized height, such as eight inches, has a spacing at the ¼ points, such as four inches, and has a set standardized width, such as 16 inches.

Referring now to FIG. 3, The form tie connector 12 can be shaped to fit in a dovetail channel 22 for insertion into interior and exterior shell items (masonry shells 20, described below). The form tie connector 12 can be slightly oversized such that force is required to insert form tie connector 12 into dovetail channel 22. The form tie connector 12 can be tapered at the bottom to allow for ease of insertion into dovetail channel 22. The form tie connector 12 can have a tab 16 extension for insertion into cross tie 10, ½″ diameter plastic pipe. This connection can be glued or screwed to assure proper resistance to any loads present. The form tie connector 12 can have a cross shaped tongue 14 extending above for insertion of the tongue receiver channel 44 in receiver connector 40. The form tie connector 12 can have a cross shaped taper 15 to allow for ease of insertion of the receiver connector 40 onto the form tie connector 12.

Referring now to FIG. 2B, The cross tie member 10 can be cut to size from a length of ½″ diameter plastic pipe. The cross tie member 10 can attach to form tie connector 12 on both ends of cross tie member 10 by inserting tab 16 extension into cross tie member 10. Cross tie member 10 acts as tension ties to resist the pressure exerted when pouring the concrete core 70 (see FIG. 2A) against the exterior and interior walls acting as a concrete form. Cross tie member 10 can act as guide and restraint for rigid insulation segment 50. Cross tie member 10 must be of a uniform geometric shape to allow for sliding and positioning rigid insulation segment 50. Cross tie member 10 can be cut to any length. The length of cross tie member 10 can equal the total thickness of the multiple layers of rigid insulation segments 50 added together plus the thickness required for the center concrete core 70.

Referring now to FIG. 4, The CMU shell 20 provides the opposing walls of a stay in place concrete form in combination with rigid insulation segments 50. CMU shell 20 consists of cement block segments with channels 22 formed at regular intervals to accept and restrain plastic connectors 12 and plastic connectors 40. CMU shells 20 are stacked one on top of another and side to side to create the opposing walls of a stay in place concrete from. CMU shells 20 are connected one on top of another by plastic connectors 12 and plastic connectors 40. CMU shells 20 are retrained within a grid system to maintain a uniform height by adjusting the height of the CMU shell 20 and Connectors 12 & 40 combined through a telescoping friction connection configuration.

Referring now to FIG. 3, The form tie connector 40 can be shaped to fit in a dovetail channel 22 for insertion into the bottom of interior and exterior shell items (masonry shells 20, described above). The form tie connector 40 can be slightly oversized such that force is required to insert form tie connector 40 into dovetail channel 22. The form tie connector 40 can be tapered to allow for ease of insertion into dovetail channel 22. The form tie connector 40 can have a cross shaped tongue 44 indentation for insertion of the tongue extension 14 from form tie connector 12. Alternatively, form tie connector 40 and form tie connector 12 can be molded as one member half inserted into channel 22 of one block 20 and half inserted into channel 22 of the next block 20 above. Adjustment of the height of the assembly would occur by the telescoping friction connection between channel 22 and the combined form tie connector 12 plus 40.

Referring now to FIG. 5A and 5B, The rigid insulation segments 50 are rectangular shaped segments of rigid insulation with clip corners that are positioned in place by restraining the segments between a grid formed by cross tie members 10. Rigid insulation segments 50 together with CMU blocks 20 form the opposing walls of a stay in place concrete form system. Rigid insulation segments 50 can be installed in multiple layers as required to meet the insulation requirements set forth by the designer. Rigid insulation segments 50 can be installed after the cross tie members 10 are in place by inserting the rigid insulation segments 50 between the cross ties 10 rotated at a 45 degree angle and then twist the segments parallel to CMU shell 20. Rigid insulation segments can then be slid to either the exterior shell or the interior shell along geometrically uniform shaped cross tie member 10 as required.

Referring now to FIG. 6A and 6B, mortar from behind 60 can be provided to increase the stiffness of the stay in place concrete form system, keeping the wall plumb until the center concrete core 70 (see FIG. 2A) can cure. Mortar from behind 60 can bond 2 course of CMU block 20 together by overlapping ½ the height of each block when poured in a cavity behind each block and then curing to bond the two blocks together similar to mortar place between blocks. The cavity required to place mortar from behind 60 is achieved by moving rigid insulation segment 50 away from CMU Block 20 by sliding the segment along its retraining cross tie members 10. The friction between cross tie member 10 and rigid insulation segment 50 maintains the cavity as required.

Referring now to FIG. 2A, The concrete wall 70 is a reserved space for the concrete wall designer. The designer will determine the reinforcement and compression strength and thickness of this element. Vertical reinforcing rods, such as concrete rebar, can be placed before assembling the block wall.

Referring now to FIG. 2B, The plastic cross ties 10 can be supplemented to resist the horizontal hydraulic pressure of the poured concrete 70 by drilling standard metal form ties 80 through shells 20 or in the joints between shells 20 and resting in a position inside of plastic cross tie 10. Standard form ties 80 would include large washers on either end to restrain both the exterior and interior shells 20.

The elements of the present invention can be stacked similarly to masonry block construction one course at a time. However, unlike masonry block construction, the elements of the present invention create a stay-in-place concrete wall form. The concrete wall inside becomes the structural element. The stay-in-place form adds an exterior and interior finish. The lightweight concrete insulation 60 provides insulation value, fire resistance, sound deadening characteristics, and moisture resistance along with bonding to the shells 20. The rigid insulation 50 provides additional insulation value to the completed assembly.

The exterior masonry shell 20 can act as the exterior finish, eliminating a step in the construction process. The assembly eliminates the need to strip and remove concrete forms as the forms stay-in-place. Masonry walls create thermal bridges and the plastic cross tie 10 with rigid insulation 50 reduces the thermal bridge and saves on heating and cooling costs. The rigid insulation 50 and lightweight concrete insulation 60 combined can provide the code required insulation values and eliminate another step in the construction process.

The lightweight concrete insulation 60 forms two vertical enclosed surfaces tied together by plastic form tie ladders 10 at close spacing to facilitate concrete wall construction.

In one embodiment, the plastic members can be made from polypropylene. Molds conforming to the configurations shown in the attached figures are constructed. Each plastic piece is then reproduced repeatedly using an injection molding process.

The masonry shells 20 are configured to be compatible with standard concrete masonry unit manufacturing methods. Required amounts of sand, gravel, and cement are transferred to a weigh batcher who measures the proper amounts of each material. In the block machine, the concrete is forced downward into molds. The molds consist of an outer mold box containing several mold liners. The liners determine the shape of the block. The concrete is compacted by the weight of the upper mold head coming down on the mold cavities.

Rigid insulation 50 can be procured in precut heights and width with the desired thicknesses.

In one embodiment, the lightweight insulating concrete 60 includes Perlite concrete. Perlite concrete can be mixed in a concrete mixer. The required amounts of water, air entraining admixture and Portland cement can be placed in the mixer and can be mixed until slurry is formed. The proper quantity of perlite concrete aggregate can then he added to the slurry and all materials mixed until design wet density is reached.

The masonry shells 20 and the plastic connectors 12 & 40 can be assembled in the plant or at the site. The plastic connectors 12 & 40 be driven into the masonry shell 20 to achieve a predetermined standard assembly height.

In warm exterior climate conditions, it might be possible to have a mass wall where high thermal mass, such as a concrete wall, is exposed to the interior of a building. The high thermal mass can absorb heat from occupants making them feel cooler.

In the present invention, there is an exterior insulation barrier and an interior insulation barrier including lightweight insulating concrete 60 and rigid insulation 50. The interior insulating barrier can have non-insulating materials substituted in warm exterior climate conditions when high thermal mass construction is desired. The interior precut rigid insulation 50 can be replaced by cement board with the same dimensions. The lightweight insulating concrete 60 can be replaced with non-insulating concrete. This would create thermal bridging from the interior to the center concrete core 70 while maintaining the thermal break from the exterior to the center concrete core 70.

The present invention would be used to form vertical concrete walls. In one embodiment, the forms would rest on continuous spread concrete footings. The mason would first position the vertical reinforcement bars required for the concrete wall to be constructed. The present invention would be laid up in courses similar to cmu block construction. In one embodiment, the course would match 8 inch heights similar to typical masonry block construction.

The first course of masonry shells and plastic form tie ladders would be joined together around the rebar and would rest in a bed of mason's mortar. The mortar would allow for adjustments in plumb and level in this first course. Future courses after the first course could be dry stacked.

Rigid insulation one coarse high can be inserted into the plastic form ties on both sides to create the confined space for the lightweight insulating concrete. The insulating concrete is not used until the second course is in place.

In subsequent courses the first step is to stack the CMU shells with plastic connectors onto matching CMU shells from the course below. Cross ties would then be inserted between the connectors on the interior and exterior shells and screwed or glued in place. In one embodiment the form cross ties would be spaced at 4 inch centers.

Precut rigid insulation would be slid down from the top into the form tie grid on both sides to create a confined space for pouring the two lightweight insulating concrete layers. The lightweight insulating concrete would be mixed on site and poured into each of the confined spaces so as to fill ½ of the block height from the course below and ½ of the block height of the current course being installed. When cured this will result in the two courses of shells to be bonded together with the lightweight insulating concrete. The second half of the confined spaces of the current course will be filled when the lightweight concrete for the course above is poured.

Any horizontal rebar required for the center core concrete wall can be placed and secured before proceeding to the next course.

The above steps can be repeated, coarse by coarse, until the stay-in-place concrete form reaches the desired height.

Once the lightweight insulating concrete layer has cured, the center concrete wall can be poured in one lift up to the designed height. This process creates an insulated concrete wall with an interior and exterior hard shell finish.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

What is claimed is:
 1. A stay-in-place concrete wall form system with interior and exterior cementitious segmental shells for assembly on site within a predetermined grid course pattern that is properly spaced by telescoping plastic friction connectors comprising of: Cementitious shell channels formed along a height of cementitious shells, the cementitious shell channels spaced apart by a spacing; A plastic friction connector assembly having a first protrusion on a bottom half of the connector and a second protrusion on a top half of the plastic connector, the first protrusion operable to fit into the cementitious shell channels below and the second protrusion operable to fit into the cementitious shell channels above and the assembly operable to accept a cross tie member; A cross tie member operable to disposed on plastic friction connector assembly fitting attached to an exterior shell assembly and the opposite end operable to disposed on plastic friction connector assembly fitting attached to an interior shell assembly; and First and second rigid insulation form liners operable to disposed on each end of the cross tie members.
 2. The stay-in-place concrete wall system of claim 1, further comprising an plastic pipe disposed on the plastic friction connector assemblies to retain the first and second rigid insulation form liners.
 3. The stay-in-place concrete wall system of claim 1, wherein the cementitous shell channels are dovetail shaped channels.
 4. The stay-in-place concrete wall system of claim 1, where the cementitious shells are concrete masonry units.
 5. The stay-in-place concrete wall system of claim 1, further comprising a spacer stop adapted to space a cavity between the rigid form liners and the the cementitous shells to allow for mortaring behind the cementitous shells.
 6. The stay-in-place concrete wall system of claim 1, further comprising plastic friction connector assemblies made of multiple plastic parts that attach together.
 7. The stay-in-place concrete wall system of claim 1, further comprising of metal form ties contained within the plastic cross ties to restrain the shells against hydraulic pressure of poured concrete.
 8. The stay-in-place concrete wall system of claim 1, further comprising concrete poured in a central region, between the first and second rigid insulation form liners.
 9. A method for forming a stay-in-place concrete wall system comprising: disposing cementitious shells where a concrete wall is desired, the cementitious shells having channels at a spacing to accept plastic connectors, the cementitious shells arranged to form an interior and exterior wall of a stay-in-place form; assembling plastic connectors in pairs with plastic cross ties, sliding the assembly into the shell channel in the exterior cementitious shell while simultaneously sliding the assembly into the shell channel in the interior cementitious shell, a force is applied upon the plastic connectors until bottom half of plastic assembly is embedded into the shell channel. securing first and second rigid insulation form liners on each end of uniform plastic cross tie assembly, the rigid insulation restrained between a grid of cross ties spanning between the exterior cementitious shell and the interior cementitious shells, uniform cross tie geometry allows rigid insulation to be position as required along its length; sliding a cementitious shell onto an exterior side of the plastic cross tie assembly, the cementitious shell having cementitious shell channels formed along a height of the cementitious shell, the cementitious shell channels spaced apart by a spacing and adapted to receive the top half of the protrusion, a force is applied until the cementitious shell is properly spaced within a predetermined grid dimension pattern; sliding a cementitious shell onto an interior side of the plastic cross tie assembly, the cementitious shell having cementitious shell channels formed along a height of the cementitious shell, the cementitious shell channels spaced apart by a spacing and adapted to receive the top half of the protrusion, a force is applied until the cementitious shell is properly spaced within a predetermined grid dimension pattern; and repeating steps above on course by course grid level until exterior and interior wall assemblies are stacked to the required height.
 9. The methods of claim 8, further comprising of patching or pointing the cementitious shell joints after the shells are positioned onto the plastic cross tie assemblies.
 10. The method of claim 8, wherein the rigid insulation liners are positioned with a cavity between the liners and the cementitious shells to accept course by course mortar from behind.
 11. The methods of claim 8, wherein the cementitious shells are concrete masonry units.
 12. The methods of claim 8, wherein the masonry shell channels are dovetail shaped channels.
 13. The methods of claim 8, wherein the uniform cross ties are plastic piping.
 14. The methods of claim 8, wherein plastic connectors consist of multiple plastic parts that attach together.
 15. The methods of claim 8, wherein metal form ties can be threaded through the plastic ties to supplement the plastic cross ties.
 16. The method of claim 6, further comprising pouring concrete in a central region, between the first and second rigid insulation form liners. 